1. Field of the Invention
The present invention relates to a technique of a microscope, and more particularly, to a technique of a data communication made among the component units of a microscope system in order to electrically control the switching or the driving operations of various types of members provided in the microscope system.
2. Description of the Related Art
Recent microscopes have been put into components, and many of them adopt a unit configuration that is implemented by using optical functional units as a base (for example, see Japanese Published Unexamined Patent Application No. 2005-157340). Since optical elements required for an observation method, which is chosen according to an intended use, can be selected and combined for such microscopes, they can efficiently support various types of observation methods. Specifically, various types of units, in which optical elements such as objective lenses of multiple magnification factors, an optical filter, and the like are incorporated, are provided as the component units of a microscope. Such component units are configured so that a plurality of comprised optical elements can be switched. Additionally, some of such component units are configured to be attachable/detachable to/from a microscope.
In a microscope system constructed as an assembly of such various units, a controller that governs the control of the entire system, and units are interconnected with diverse cables in order to enable various types of data to be transmitted/received between the controller and the units. These cables can sometimes become long due to restrictions imposed on the arrangement of the controller and the units, leading to the possible lack of the neatness of the system. Additionally, influences on magnetic performance are unignorable in some cases.
As one means for overcoming such a situation, there is a method for controlling a microscope system with a controller area network (CAN) protocol. With CAN, a distributed control is performed, and data is transmitted/received by connecting a controller, which is comprised for each component unit, with a serial communication, so that an operation for controlling the entire system is performed. With this configuration, exclusive control wires from a controller are collected within a unit, and a bus (CAN bus) connection can be made as a connection for a data communication made among component units, whereby the degree of freedom of the configuration of the entire system is improved, and at the same time, improvements in wiring savings and performance can be expected.
Concerning the present invention, for example, Japanese Published Unexamined Patent Application No. 2000-165415, Japanese Published Unexamined Patent Application No. 2002-140139, and Japanese Registered Patent Publication No. 3538366 disclose the techniques for enabling a CAN bus to be suitably terminated.
In a microscope system having the above described unit configuration, a user normally performs operations for choosing a unit comprising an optical element required according to an observation method, and for assembling the microscope system. However, if the above described CAN is used for the system control of the microscope system, 2 ends (both ends) of a CAN bus, which is a two-wire line, must be terminated. If the ends are not properly terminated, problems such as a system startup failure, or the like can occur. It is difficult for a normal user to perform the operations for assembling the microscope system in consideration of this point.
To solve such a problem, the technique for automatically causing a unit in a succeeding stage to terminate a CAN bus if the unit is connected in the stage succeeding a local unit is known (for example, see the above described Japanese Published Unexamined Patent Application No. 2002-140139 and the above described Japanese Registered Patent Publication No. 3538366).
With such a mechanism for automatically moving the termination position of a bus according to a connection of units, a problem of making multiple terminations, and a problem of missing a termination can be avoided. However, if a unit is added by using this mechanism, the unit must be added at the end of a bus, or must be interposed by once interrupting a bus. Namely, also with this mechanism, a user must assemble a microscope system by connecting units in consideration of their interconnections so that both ends of a bus are properly terminated. Therefore, the degree of difficulty of the assembly operations is still high. Additionally, since there are not a few cases where a combination of units is changed according to an intended use in a microscope system, a connection error can be possibly caused during the repetitions of an assembly.